In 2006 Comverse asked us to help with the systems integration of their latest product acquisition.
Comverse had just acquired another company at the time and was trying to integrate their front-end into the existing back-end.
This project consisted of building a J2EE framework. I looked at this as seeing how the other half lived. We were able to pick J2EE up pretty quickly as it had a lot of parallels with the .NET world. My task was to put together patterns and practices for extensibility models for their next-gen product. This included learning swing, spring, java beans, etc.
Our contribution was a proof of concept showing various patterns to use for extensibility.